Autonomous relative positioning using electromagnetic signals between two or more objects is important in many applications. In a formation of a plurality moving members, precise determination of the relative attitude, the attitude rate, and the relative position is necessary. In certain formation applications, such determination may be achieved in real time or near real time. These high precision measurements may preferably be carried out automatically and reliably without human intervention or constant maintenance in order to meet requirements of specific applications and to reduce system operation cost.
For example, the Deep Space Mission 3 (DS-3) under the New Millennium Program (NMP) of the National Aeronautics and Space Administration (NASA) uses a separated spacecraft interferometry system (SSI) in deep space to obtain high resolution images. One particular architecture presently under consideration for SSI uses three spacecraft traveling in a triangular formation relative to one another to form an optical interferometer. One of the challenges is to devise a sensing system capable of autonomously maintaining the relative positioning and attitude of three spacecraft in a formation. Such a system should be low-power, low mass, and low cost.
In addition, the system should have a general architecture which would enable it to be used on a variety of different missions without significant re-engineering.